Leaching system cavity of preformed components

ABSTRACT

Structural components for providing a subsurface cavity over a leach bed for the distribution of liquid effluent in which the component elements are primarily flat roof elements of a rectangular shape, wall elements having vertical wall portions and horizontal roof portions, corner elements in which the vertical wall portions extend around a right angle and supporting elements for providing subsupport at the conjunctions of the other elements.

United States Patent 1191 1111 3,910,051 Komisarek 5] Oct. 7, 1975 [5 LEACHING SYSTEM CAVITY 01 3,295,272 1/1967 Kanno 52/126 PREFORMED COMPONENTS 3,501,007 3/1970 Davis v 210/170 [76] I t J h A K k A h t 3,535,236 10/1970 Travis 210/242 X nven or: osep omlsare m ers Road, Bedford, NH 031-02 FOREIGN PATENTS OR APPLICATIONS 836,473 0000 Germany 61/11 [22] Flledi May 3, 1974 1,208,933 10/1970 United Kingdom... 61/10 F10.2 29,121 2/1911 UIlllIGd Kingdom 61/10 I Primary Examiner-Dennis L. Taylor [52] U.S. Cl. 61/11; 61/13; 210/170 A to n y, Ag nt, or Firm- Thomas N, Tarrant [51] Int. Cl. EOZB 11/00 [58] Field of Search 61/10, 11, l2, 13; 52/126, 57] CT 52/303 569; 210/118 170 Structural components for providing a subsurface cavity over a leach bed for the distribution of liquid efflu- [56] References cued ent in which the component elements are primarily UNITED STATES PATENTS flat roof elements of a rectangular shape, wall ele- 349,735 9/1886 Nicaise 61/10 X ments having vertical wall portions and horizontal roof ,9 l /l915 Terry 210/170 portions, corner elements in which the vertical wall 213731239 Myron 61/11 X portions extend around a right angle and supporting 2,802,339 8/1957 Fogerty 61/11 elements for providing subsupport at the conjunctions 2,956,653 10/1960 Llskey 52/126 X of the other elements 3,067,843 12/1962 Rushtoh et alm. 52/126 3,279,134 10/1966 Donovan 52/126 10 Claims, 2 Drawing Figures U.S. Patent Oct. 7,1975 3,910,051

LEACHING SYSTEM CAVIITY OF FRIEFORIVMD COMPONENTS BACKGROUND or THE INVENTION 1. Field of the Invention The present invention relates to leaching systems for effluent and in particular to such systems in which a covering structure is positioned over the leaching bed providing a cavity therebetween.

2. Description of the Prior Art The purpose of a leaching field is to provide a large surface area contact for the absorption of effluent into the subsurface soil. The most customary method of doing this is to run great lengths of drainage tile install ing the tile in much larger beds of gravel, afterwards covering the gravel with tar paper or some other soil impermeable material so that the interstices between the pieces of gravel do not get filled with soil; The effluent passes from the drainage tile into the gravel and the gravel presents a large surface area contact to the surrounding subsoil. Systems of this nature are fairly expensive, require excavating large areas of land and are costly and difficult to repair when blockages occur. A desirable alternative is to excavate one large hole, prepare the bottom of the hole with a suitable leaching bed of grave] or the like and then install a structure over the leaching bed that leaves a spacious cavity for the distribution of effluent liquid. The structure prevents subsur face soil from penetrating into the interstices of the gravel bed and the only spaces small enough to present clogging problems are the gravel interstices themselves. This type of system can be relatively inexpensive to install, trouble free in operation and easy to repair.

Cavity forming structures for the distribution of liquid effluent were known even before the present widespread use of septic tanks. For example. see Winfield, British Pat. No. 3945 dated K90 i and Ames. British Pat. No. E6332 dated 1912. These early structures were used to distribute the liquid effluent output from filter beds. More recent structures are found in the seeping wells of Eads, US. Pat. No. 2,767,lil and the arched vaults of Nicholson. US. Pat. No. 2,866,319. The most recent structures widely used for this purpose are exemplified by Gogan. et al., US. Pat. No. 3,339,366 and LalVlonica, US. Pat. No. 3,64l5,lll. These last two use precast concrete construction having generally rectangular shapes and flat tops. While they could be used singly, they are more commonly installed in clusters. The individual units disclosed in the last two patents are massive and difficult to handle on a construction site. If the individual units were made smaller with the same design, the amount of concrete consumed in the construction would be needlessly excessive.

SUMMARY OF THE INVENTION and corner elements which have surfaces extending in three mutually perpendicular planes. The fourth element is a simple supporting member for positioning at the junctions of the other elements for providing vertical support. When these elements are assembled, in construction on site, a cavity of any desired size is produced with a flat roof, side walls all around and a large cavity extending between the walls interrupted only by the supports positioned at the junctures or other elements.

Thus, it is an object of the present invention to provide a new structure for the distribution of liquid effluent to a leaching bed.

It is a further object of the invention to provide a cavity for distribution of liquid effluent to leaching beds which is made up of simple, preformed components easily assembled into a unitary whole structure at the construction site.

It is a further object of the present invention to provide a cavity for the distribution of liquid effluents to leaching beds which may readily be made in any desired size utilizing the same preformed components.

Further objects and features of the invention will be understood upon reading the following description to gether with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a perspective view partially exploded showing a cavity forming structure over a leaching bed in accordance with the invention;

FIG. 2 is section taken along line 22 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The function ofa leaching chamber is to provide and maintain a large-area, shallow cavity for the spreading of effluent liquid to promote its wide-area contact with and absorption into the leaching bed below. In order to perform this function the leaching chamber structure must adequately support the soil above and prevent it from penetrating into and clogging the chamber cavity. Leaching chamber 10, as shown in the drawing, performs this function in an unusually simple manner.

Chamber i0 is made up of rectangular flat roof elements ll bounded by wall elements 12 having horizontal roof portions 15 and vertical wall portions l6. Wall elements 112 have an L shaped cross-section in which the long arm of the L is roof portion 15 and the short arm of the L forms wall portion 16. In addition to ele ments ill and 12, chamber 10 has four corner elements M of a similar configuration to elements 12. Corner elements l4 have a roof portion 17 and two wall portions l8 and 2d at right angles to each other to form a corner. Thus elements 14 have surfaces extending in three mutually perpendicular planes. A fourth element is pedestal 21 or similar support member which provides support at the junctions 22 of the other elements. As depicted in the drawing, the structure is put together in a rectangular configuration with flat elements 11 forming the center portion and the side portions being formed ofelernents l2 and lid with a corner element 14 at each of the four corners of the rectangular shape.

One of pedestals 21 is positioned at the corner junctures 22 where each element meets with three other elements. Thus each pedestal 21 supports the corners of four elements simultaneously at juncture 22.

The leaching chamber is positioned over a leaching bed 24 of conventional character. Commonly this will be an excavated area which has been prepared with a depth of sand and gravel adequate to insure absorption of the distributed liquid effluent.

It is contemplated the components 1 1, l2, l4 and 21 be preformed from plastic, tile, concrete or other appropriate structural material. The presently preferred form is reinforced concrete having adequate strength to support any probable load from overhead soil as well as vehicles or other loads that may pass over the site. The concrete may be from 2 to 8 inches thick depending on the overall size, the reinforcing steel and the extent to which portion of the elements are thinned out to conserve concrete. While roof elements 11 may be completely planar, it is considered preferable to cast them as well as elements 12 and 14 with thickened cross or diagonal strengthening ridges so that they are relatively thin, i.e., 2 inches, except at the ridges and edges. This is well known in preformed concrete construction so it has not been detailed in the Drawing. FIG. 2 does partially depict the thicker and thinner parts of elements 11.

A desirable size of the elements for domestic installations is with a weight of up to about 1500 pounds. For elements 11 the suitable dimensions would then be about 4 feet by 4 feet. These figures are selected to permit handling by the usual equipment used by contractors for domestic systems. Also for easy handling, metal hoops are precast into each of elements l2, l4 and 11. While not illustrated, these hoops would be made of iron bars which either loop around the reinforcing steel in the element or have portions that extend laterally inside the concrete to distribute the lifting stress when these elements are being moved or positioned.

For the introduction of effluent, some of the members 12 will be formed with apertures 26 for the connection of effluent carrying pipe 27. Similarly, some of the elements will have apertures 28 in their roof portion for the connection of vent pipes 30.

While the illustrated leaching chamber 10 has only one pipe 27 connecting to a wall 16, particularly in larger chambers it would be desirable to connect other pipes at the wall and in some cases desirable to extend further pipes inside the chamber to improve distribution.

Upon construction of a leaching chamber according to the invention, it is desirable to seal the joints between the elements. This sealing may be provided by pouring hot tar 29 or by the use of caulking guns with a suitable caulking compound. Plastic sheeting or roofing paper can also be used to cover the top of the chamber to prevent penetration of overlying soil through cracks. Some-form of interlocking edge design is also readily usable or the preattachment of resilient gasketing around each element.

While apertures 28 are provided for ventilating pipes 30, some of them are also conveniently used for inspec-' tion holes and when so used, are suitably plugged by plug 31 which may be made of concrete having a bale 32 imbedded in the concrete as a handle.

Although the weight of the elements ll, l2, l4 and 21 is sufficient to hold them in place once positioned, some interlocking is desirable and is easily provided. As depicted in FIG. 2, the corners of the elements 11, 12 and 14 are provided with projecting nubs 35 where they fall over supporting elements 21. Supporting elements 21 are provided with mating recesses 34. One of the primary advantages in the use of such interlocks arises in positioning the elements. Since recesses and nubs 34 and 35 are precast, they provide a good deal of precision. In placing the elements at a construction site there is not only a definite feel added as the pieces interlock, but when an element is out of position it becomes obvious as a discontinuity in the surface of the structure. While only one form of interlocking is depicted, the use of any other conventional interlocking construction is contemplated.

In constructing leaching chambers according to the invention, the leaching bed is prepared and carefully leveled and compacted. Next, the leaching chamber is constructed element by element until complete. After connection of pipes and sealing of the joints the surface soil is returned on top of the chamber and it is ready for operation. If, during its use, some malfunction occurs, the surface soil must be removed but the inspection plugs 31 can be lifted to determine the exact location of the malfunction and avoid unnecessary moving of the elements. Repairs are easily accomplished by removing only the elements in the area of the malfunction correcting the cause of the defect, returning those elements and rescaling.

In some cases it could be desirable to raise the height of the entire structure. To facilitate this it is contemplated to cast pedestals 21 with complementary discontinuities on top and bottom. That is, nubs on top and recesses on the bottom or vice versa. (It will be recognized that the tops of pedestals 21 may have the nubs and the recesses would then be in the bottoms of ele-' ments ll, 12 and 14.) The pedestals can then be stacked for greater height. To raise the walls equally, it is contemplated to cast blocks (not shown) matching the bottom edges of elements 12 and 14 and of a thickness equal to pedestals 21. Such blocks would preferably have discontinuities interlocking with discontinuities in the bottom edges of elements 12 and 14. Thus the present invention provides flexibility for cavityheight as well as area.

While the invention has been described with respect to a specific embodiment, various modifications are contemplated as within the scope of the invention. Thus it is contemplated that while the invention permits the ready use of small elements for domestic use, elements for commercial use would run up into the range of 64 square feet and larger in size. Further, although a rectangular configuration has been described for its flexibility in overall size variation, circular, elliptical and various polygonal configurations canreadily be designed without departing from the spirit of the invention. It is of particular value that leaching chambers in accordance with the invention can be made of any desired size utilizing the same elements merely by adding in additional roof and side elements. Thus the invention can be used for a wide variety of domestic and industrial subsurface sewage disposal systems and it is intended to cover the invention within the full scope of the following claims.

I claim:

1. A leach field construction for distributing fluid waste comprising:

a. a leach bed;

b. a plurality of discrete roof elements positioned adjacent each other over said leach bed;

a plurality of discrete side elements each having roof portions and wall portions positioned around and adjacent to said roof elements;

a plurality of discrete support elements positioned under each four-way conjunction of said roof elements and said side elements for supporting each said conjunction at a level with said wall portions, said roof, side and support elements being arranged to provide a single roofed cavity;

e. an entrance line connected through one of said elements for ingress of fluid waste to said cavity; and,

f. sealing means for preventing passage of material downward between the interstices of adjacent ones of said roof elements and between adjacent ones of said side elements.

2. A leach field construction according to claim 1 wherein said roof elements, said side elements and said cavity-forming structure are individually substantially rectangular in shape.

3. A leach field construction according to claim 2 wherein at least four of said side elements each have two mutually perpendicular adjacent wall portions and form the comers of said leach field construction.

4. A leach field construction according to claim 3 wherein the wall portions of said side elements are solid and contiguous providing a substantially continuous perimeter wall.

S. A leach field construction according to claim 1 wherein said roof elements, said side elements and said support elements are all formed from precast concrete.

6. A leach field construction according to claim 1 wherein adjacent roof and side elements are sealed at their adjoining edges by sealing material.

7. A leach field construction according to claim 1 wherein said support elements are rectangular blocks.

8. A leach field construction according to claim 7 wherein said support elements each has a surface discontinuity at each corner, said roof elements each has a surface discontinuity at each corner shaped to mate with a discontinuity on a respective support element whereby interlocking of said construction is achieved.

9. A leach field construction according to claim 8 wherein said side elements each has a surface discontinuity at each inner comer shaped to mate with a discontinuity on a respective support element.

10. A leach field construction according to claim 1 positioned over a gravel leach bed and having at least one first pipe for introducing effluent connected through a wall portion, at least one second pipe directed vertically from a roof portion as a vent, and a plurality of metal bails connected one to each of said roof and side elements for handling. 

1. A leach field construction for distributing fluid waste comprising: a. a leach bed; b. a plurality of discrete roof elements positioned adjacent each other over said leach bed; c. a plurality of discrete side elements each having roof portions and wall portions positioned around and adjacent to said roof elements; d. a plurality of discrete support elements positioned under each four-way conjunction of said roof elements and said side elements for supporting each said conjunction at a level with said wall portions, said roof, side and support elements being arranged to provide a single roofed cavity; e. an entrance line connected through one of said elements for ingress of fluid waste to said cavity; and, f. sealing means for preventing passage of material downward between the interstices of adjacent ones of said roof elements and between adjacent ones of said side elements.
 2. A leach field construction according to claim 1 wherein said roof elements, said side elements and said cavity-forming structure are individually substantially rectangular in shape.
 3. A leach field construction according to claim 2 wherein at least four of said side elements each have two mutually perpendicular adjacent wall portions and form the corners of said leach field construction.
 4. A leach field construction according to claim 3 wherein the wall portions of said side elements are solid aNd contiguous providing a substantially continuous perimeter wall.
 5. A leach field construction according to claim 1 wherein said roof elements, said side elements and said support elements are all formed from precast concrete.
 6. A leach field construction according to claim 1 wherein adjacent roof and side elements are sealed at their adjoining edges by sealing material.
 7. A leach field construction according to claim 1 wherein said support elements are rectangular blocks.
 8. A leach field construction according to claim 7 wherein said support elements each has a surface discontinuity at each corner, said roof elements each has a surface discontinuity at each corner shaped to mate with a discontinuity on a respective support element whereby interlocking of said construction is achieved.
 9. A leach field construction according to claim 8 wherein said side elements each has a surface discontinuity at each inner corner shaped to mate with a discontinuity on a respective support element.
 10. A leach field construction according to claim 1 positioned over a gravel leach bed and having at least one first pipe for introducing effluent connected through a wall portion, at least one second pipe directed vertically from a roof portion as a vent, and a plurality of metal bails connected one to each of said roof and side elements for handling. 